Referring to FIG. 1, a plot of the current-voltage characteristics of an exemplary p-n junction (e.g., semiconductor junction) diode and an exemplary Schottky (e.g., semiconductor-metal junction) diode, in accordance with the conventional art, is shown. It is appreciated that the plots are for illustrative purposes and do not necessary represent a particular p-n junction diode or Schottky diode. In a forward-biased state, the p-n junction diode typically has a fully conducting voltage drop of approximate 1V, for large currents. In a reverse-biased state, a leakage current, which is proportional to the junction area, flows in the p-n junction diode. The leakage current exhibits a strong temperature dependence, approximately doubling for every 10° C. rise in temperature. If the reverse-biased voltage exceeds the breakdown voltage of the device, the reverse current increases rapidly.
The leakage current characteristics and breakdown voltage of p-n junction diodes may readily be utilized in rectifier applications and the like. However, the voltage drop across the p-n junction diode during forward-biasing results in significant power consumption when relatively large currents flow through the p-n junction diode.
In a forward-biased state, the Schottky diode typically exhibits a fully conducting voltage drop of approximate 0.5V, for large currents. In a reverse-biased state, a substantial leakage current flows at relatively low reverse voltages. The Schottky diode also exhibits a weak “knee” as the device enters breakdown. Thus, the Schottky diode suffers from both a higher leakage current and a low breakdown voltage in the reverse-biased direction, as compared to a p-n junction diode.
The reduced voltage drop across the Schottky diode during forward-biasing would make the device advantageous for use in rectifier applications and other similar applications. However, the substantial leakage current and relatively low breakdown voltage limits use of the Schottky diode to low voltage applications.
Thus, in the conventional art the use of diodes, in rectifier applications and the like, suffer from higher forward voltage drop, higher leakage current and/or low breakdown voltage.